avnish aggarwal / Mbed 2 deprecated Book-PE_09-10_Metronomex

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Dependencies:   mbed

Fork of Book-PE_09-10_Metronome by avnish aggarwal

main.cpp@1:733a0de4d34c, 2013-08-01 (annotated)

Committer:
avnisha
Date:
Thu Aug 01 23:24:00 2013 +0000
Revision:
1:733a0de4d34c
Parent:
0:d7c850cdbc39 
based on toulson

Who changed what in which revision?

UserRevisionLine numberNew contents of line
robt 0:d7c850cdbc39 1 /*Program Example 9.10: Metronome. Uses Ticker to set beat rate
avnisha 1:733a0de4d34c 2
avnisha 1:733a0de4d34c 3
avnisha 1:733a0de4d34c 4 //BusIn joy(p15,p12,p13,p16);
avnisha 1:733a0de4d34c 5 */
robt 0:d7c850cdbc39 6 #include "mbed.h"
robt 0:d7c850cdbc39 7 #include <stdio.h>
robt 0:d7c850cdbc39 8 Serial pc(USBTX, USBRX);
avnisha 1:733a0de4d34c 9 DigitalIn up_button(p15);
avnisha 1:733a0de4d34c 10 DigitalIn down_button(p16);
avnisha 1:733a0de4d34c 11 DigitalOut redled(LED1); //displays the metronome beat
robt 0:d7c850cdbc39 12 Ticker beat_rate; //define a Ticker, with name “beat_rate”
robt 0:d7c850cdbc39 13 void beat(void);
avnisha 1:733a0de4d34c 14 float period (1); //metronome period in seconds, inital value 0.5
avnisha 1:733a0de4d34c 15 int rate (60); //metronome rate, initial value 120
robt 0:d7c850cdbc39 16
robt 0:d7c850cdbc39 17 int main() {
robt 0:d7c850cdbc39 18 pc.printf("\r\n");
robt 0:d7c850cdbc39 19 pc.printf("mbed metronome!\r\n");
robt 0:d7c850cdbc39 20 pc.printf("_______________\r\n");
robt 0:d7c850cdbc39 21 period = 1;
robt 0:d7c850cdbc39 22 redled = 1; //diagnostic
robt 0:d7c850cdbc39 23 wait(.1);
robt 0:d7c850cdbc39 24 redled = 0;
robt 0:d7c850cdbc39 25 beat_rate.attach(&beat, period); //initialises the beat rate
robt 0:d7c850cdbc39 26 //main loop checks buttons, updates rates and displays
robt 0:d7c850cdbc39 27 while(1){
robt 0:d7c850cdbc39 28 if (up_button ==1) //increase rate by 4
robt 0:d7c850cdbc39 29 rate = rate + 4;
robt 0:d7c850cdbc39 30 if (down_button ==1) //decrease rate by 4
robt 0:d7c850cdbc39 31 rate = rate - 4;
robt 0:d7c850cdbc39 32 if (rate > 208) //limit the maximum beat rate to 208
robt 0:d7c850cdbc39 33 rate = 208;
robt 0:d7c850cdbc39 34 if (rate < 40) //limit the minimum beat rate to 40
robt 0:d7c850cdbc39 35 rate = 40;
robt 0:d7c850cdbc39 36 period = 60/rate; //calculate the beat period
robt 0:d7c850cdbc39 37 pc.printf("metronome rate is %i\r", rate);
robt 0:d7c850cdbc39 38 //pc.printf("metronome period is %f\r\n", period); //optional check
robt 0:d7c850cdbc39 39 wait (0.5);
robt 0:d7c850cdbc39 40 }
robt 0:d7c850cdbc39 41 }
robt 0:d7c850cdbc39 42
robt 0:d7c850cdbc39 43 void beat() { //this is the metronome beat
robt 0:d7c850cdbc39 44 beat_rate.attach(&beat, period); //update beat rate at this moment
robt 0:d7c850cdbc39 45 redled = 1;
robt 0:d7c850cdbc39 46 wait(.1);
robt 0:d7c850cdbc39 47 redled = 0;
robt 0:d7c850cdbc39 48 }
robt 0:d7c850cdbc39 49